BUG: close #811, fix index.intersection where indices are incomparable

RELEASE.rst

@@ -49,6 +49,7 @@ pandas 0.7.1
   - Fixed bug whereby bool array sometimes had object dtype (#820)
   - Fix exception thrown on np.diff (#816)
   - Fix to_records where columns are non-strings (#822)
+  - Fix Index.intersection where indices have incomparable types (#811)
 
 pandas 0.7.0
 ============

pandas/core/index.py

@@ -452,12 +452,15 @@ def intersection(self, other):
             return this.intersection(other)
 
         if self.is_monotonic and other.is_monotonic:
-            result = self._inner_indexer(self, other.values)[0]
-            return self._wrap_union_result(other, result)
-        else:
-            indexer = self.get_indexer(other.values)
-            indexer = indexer.take((indexer != -1).nonzero()[0])
-            return self.take(indexer)
+            try:
+                result = self._inner_indexer(self, other.values)[0]
+                return self._wrap_union_result(other, result)
+            except TypeError:
+                pass
+
+        indexer = self.get_indexer(other.values)
+        indexer = indexer.take((indexer != -1).nonzero()[0])
+        return self.take(indexer)
 
     def diff(self, other):
         """

pandas/tests/test_frame.py

@@ -1745,6 +1745,17 @@ def test_to_records_floats(self):
         df = DataFrame(np.random.rand(10,10))
         df.to_records()
 
+    def test_join_str_datetime(self):
+        str_dates = ['20120209' , '20120222']
+        dt_dates = [datetime(2012,2,9), datetime(2012,2,22)]
+
+        A = DataFrame(str_dates, index=range(2), columns=['aa'])
+        C = DataFrame([[1,2],[3,4]], index=str_dates, columns=dt_dates)
+
+        tst = A.join(C, on = 'aa')
+
+        self.assert_(len(tst.columns) == 3)
+
     def test_from_records_sequencelike(self):
         df = DataFrame({'A' : np.random.randn(6),
                         'B' : np.arange(6),

pandas/tests/test_index.py

@@ -649,6 +649,15 @@ def test_intersection(self):
                                                      other.values)))
         self.assert_(np.array_equal(result, expected))
 
+    def test_intersect_str_dates(self):
+        dt_dates = [datetime(2012,2,9) , datetime(2012,2,22)]
+
+        i1 = Index(dt_dates, dtype=object)
+        i2 = Index(['aa'], dtype=object)
+        res = i2.intersection(i1)
+
+        self.assert_(len(res) == 0)
+
     def test_union_noncomparable(self):
         from datetime import datetime, timedelta
         # corner case, non-Int64Index